Development of a model for the prediction of the fuel consumption and nitrogen oxides emission trade-off for large ships

Abstract

a model for the prediction of the fuel consumption and nitrogen oxides emission trade-off for large ships. Energy, 80, 545-555. DOI: 10.1016/j.energy.2014 Development of a model for the prediction of the fuel consumption and nitrogen oxides emission trade-off for large ships AbstractThe international regulations on fuel efficiency and NOx emissions of commercial ships motivate the investigation of new system layouts, which can comply with the regulations. In combustion engines, measures to reduce the fuel consumption often lead to increased NOx emissions and careful consideration of this trade-off mechanism is required in the design of marine propulsion systems.This study investigates five different configurations of two-stroke diesel-based machinery systems for large ships and their influence on the mentioned trade-off. Numerical models of a low-speed two-stroke diesel engine, turbochargers and an organic Rankine cycle, are used for the optimisation of the NOx and fuel consumption at design and part-load conditions, using a multi-objective genetic algorithm. Moreover, the effects of engine tuning and exhaust gas recirculation are investigated.The results suggest that increased system complexity can lead to lower fuel consumption and NOx.Fuel consumption reductions of up to 9% with a 6.5% NOx reduction were achieved using a hybrid turbocharger and organic Rankine cycle waste heat recovery system.

Predicting Environmental Contribution to Ship’s Average Fuel Consumption Based on Non-Uniform Time Set

“…Coefficients (with 95% confidence bounds) for function (9) are: a = -1.968⋅10 5 (or alternatively -1.731⋅10 14 , 1.731⋅10 14 ), b = -0.001531 (or -131.3, 131.3), c = 1.968⋅10 5 (or alternatively -1.731⋅10 14 , 1.731⋅10 14…”

Two-Stroke Low Speed Diesel Engine Simulation Model for NOx Analysis

“…An electronically controlled engine simulated to validate the model was found to be capable of predicting NOx emissions and specific fuel oil consumption with 95 % confidence intervals. However, Larsenb et al (Larsenb et al, 2015) study looked into two-stroke diesel machinery for ships, with five varying configurations to explore the trade-off between increased NOx emissions and reduction in fuel consumption. By implementing a waste heat recovery system using an organic Rankine cycle and a hybrid turbocharger, fuel consumption decreased by up to 9 % and NOx up to 6.5 %.…”

A Comparison of Organic and Steam Rankine Cycle Power Systems for Waste Heat Recovery on Large Ships

“…The low performance at low engine loads is a consequence of the low exhaust gas temperatures. The combined performance of the diesel engine and the WHR system can be optimized by considering the simultaneous optimization of engine tuning and WHR system design [17]. Diesel engines supplied with selective catalytic reduction (SCR) employ a special tuning enabling high temperatures at low engine loads, which is required for the operation of the SCR system [62].…”

“…This point was highlighted by Baldi et al [16] who demonstrated the importance of accounting for variations in ship operation, when optimizing a marine machinery system. Larsen et al [17] studied the NO x emission and specific fuel oil consumption (SFOC) trade-off for a large marine diesel engine equipped with an ORC bottoming cycle unit while accounting for off-design operation. A combined optimization of the diesel engine, hybrid turbocharger and ORC system yielded NO x emission reductions of 6.5% and SFOC reductions up to 9%.…”